Polianthes montana Rose (1903: 11)

Castro-Castro, Arturo, González-Bernal, Marco Antonio & Aguilar, Edmi Itzel Rojas-, 2023, New insights on Polianthes montana (Asparagaceae, Agavoideae) and the description of P. aarodriguezii a new species, both from Sierra Madre Occidental, Mexico, Phytotaxa 583 (1), pp. 61-71 : 64-68

Polianthes montana Rose (1903: 11) .

Type:— MEXICO. Nayarit, Del Nayar : collected in Sierra Madre , near Santa Teresa , territorio de Tepic , 11 August 1897, J.N. Rose 2178 (holotype US!, isotypes GH!, MEXU!) . Figure 1

Perennial herb. Corm oblong (0.5–)1.2–1.9 × 1.1–1.5 cm, with growth buds and thickened contractile and fleshy roots, the roots horizontally oriented. Bulb oblong, 2.6–7.5 × 1.2–2.2 cm, covered by the persistent leaf bases. Leaves 3–6 in a basal rosette, with an additional one attached a few cm above the peduncle base, erect; alternate, ensiform, 21–30 × 0.5–1 cm, chartaceous and thickened, shiny when fresh, acute, glabrous, margin papillose-toothed, hyaline. Inflorescence racemose, 86–110 cm long, internodes decreasing in size towards the apex, with 4–12 floral nodes; scape bracts 2–6, primary sterile bract linear, 13–21 cm × 0.4–0.5 cm, apex acute, base truncate, margin papillosetoothed, primary floral bracts lanceolate to triangular, 1–1.5 × 0.27–0.34 cm, apex acute, base truncate, margin smooth, becoming scarious. Bracteoles deltoid, 1.5–2 × 0.2–0.4 mm, entire, acute, truncate. Pedicels (0.15–)0.22–0.26(–0.6) cm during anthesis, 0.34–0.36 cm in fruit, ascending. Flowers geminate, 2–2.8 × 0.34–0.5 cm, glaucous yellowish green at anthesis, white to light brown at senescence, succulent, scentless, ascending; perigone tube 1.8–2.5 × 0.3–0.5 cm at the base of the lobes, curved almost in half, tubular, clearly expanded in the middle, and again tubular to the distal part. Lobes broadly ovate, external and internal similar, inner ones sometimes slightly thinner, 2.4–3 × 1.8–2.3 mm, imbricate, slightly cucullate, acute to obtuse, papillose, both appressed to assurgent. Stamens included, filaments white, filiform, 5–5.4 mm long from their insertion into the perigone tube, inserted 0.65–0.7 cm above the ovary apex; anthers linear, 6.3–6.5 × 0.9–1 mm, yellow, included on the upper portion of the mouth of the tube in anthesis. Ovary 5.3–7.5 × 3.2–3.5 mm; style filiform, 1.7–2 cm, white, included; stigma trilobed, lobes 1.5–1.6 mm long, papillose. Fruit a loculicidal capsule, 1–1.4 × 1–1.2 cm, globose, crowned by the remains of the perigone. Seeds ovate-depressed, 3–6 × 3–5 mm, flat, dark brown, opaque.

Distribution, habitat and phenology: — Polianthes montana grows in the upper basin of the Mezquital River, in the Madrean region at the south of SMO biogeographic province ( González-Elizondo et al. 2012a, Morrone et al. 2017; Figure 2 ). It inhabits open Pinus-Quercus forests, in association with Arbutus spp. , Arctostaphylos pungens Kunth , Cosmos palmeri B.L. Rob. , Dahlia coccinea Cav. , Manfreda guttata (Jacobi & C.D. Bouché) Rose , Penstemon spp. , Pinus lumholtzii B.L. Rob & Fernald , Prochnyanthes mexicana (Zucc.) Rose , Quercus radiata Trel. , Q. jonesii Trel. , Q. viminea Trel. , and Vaccinium stenophyllum Steud. The plants are found in areas with deep and acid soils at 2100–2532 m elevation. Polianthes montana flower from early August to late September and fruit from September to late October.

Conservation status:— Polianthes montana is represented by six collections. Using GeoCAT ( Bachman et al. 2011) the extent of occurrence (EOO) is 986.8 km 2, and the size of the area of occupancy (AOO) is 24 km 2, employed cells of 2 × 2 km. Based on EOO and AOO area results, and following the IUCN (2019) criteria (EOO <5000 km 2, AOO <500 km 2, and known to exist at ± 5 locations), a preliminary category of Endangered is suggested (EN/B1a).

Taxonomic relationships: — Polianthes montana falls within Polianthes subgenus Polianthes , because it possesses white geminate flowers with filaments inserted near the midportion of the perigone tube. Polianthes montana shares morphological similarities with P. alboaustralis E. Solano & Ríos-Gómez (2014: 98) and the new species described here, but it can be differentiated by the character combination indicated in Table 2 and using the identification key included in this contribution.

The type locality of Polianthes montana is near Santa Teresa, Del Nayar, Nayarit, in the top of Sierra Madre Occidental ( Rose 1903); and recent works report it for the northeast of Jalisco state in the Chihuahuan Desert and Transmexican Volcanic Belt biogeographic provinces ( Solano 2000, Solano & Feria 2007, Barba-Gonzalez et al. 2012, Solano et al. 2018). The type material of P. montana consists of three specimens (J.N. Rose 2178, GH!, MEXU!, US!), which differ markedly from the plants of the populations reported in Jalisco. For example, Barba-González et al. (2012) and Solano et al. (2018) present some captions in their figures labelled as P. montana in their image sheets (identified with the letter O and A-B, respectively), but the photographs consists of flowers that are very different from those observed in the type materials of the species, since they have a funnel-shaped perigone, but in the P. montana type material the perigone is tubular, clearly expanded in the middle, and again tubular to the distal part. In addition, the lobes appear fully extended, but in the type materials of P. montana the lobes are appressed to assurgent. In fact, the plant shown in the plate seems closer to P. multicolor Solano & Dávila (2003: 119) , which seems possible since it coincides with its distribution area ( Figure 2 ). In contrast, the plant identified with the letter J in the plate as P. nelsonii Rose (1903: 10) by Barba-González et al. (2011), clearly corresponds to P. montana . Unfortunately, herbarium specimens are not cited in the previously mentioned works.

Material examined: — MEXICO. Durango. Mezquital: 19 km al SW de Charcos, camino a Sta. María Ocotan, 22º58’23”N, 104º29’23”W, 2250 m, 5 October 1983 (fl, fr), R. Fernández Nava 1834 ( CIIDIR!, ENCB!); La Ventana, 5.5 km al E de la localidad rumbo a Charcos, 22º57’59.3”N, 104º24’57.4”W, 2275 m, 6 August 2015 (fl, fr), J.G. González-Gallegos, B.T. Drew & J. Noriega 1863 ( CIIDIR!); km 89 de la carr. Méx. 23 Mezquital-Huazamota, 0.5 km al sur de Candelaria El Alto, 23º1’59”N, 104º32’27”W, 2161 m, 22 September 2017 (fl, fr), A. Castro-Castro et al. 4356 ( CIIDIR!, IBUG!, MEXU!, SLPM!); 15.5 km al sur de Candelaria, carretera Durango-Huazamota; 500 m antes de El Chapulín, 23.96364ºN, 104.54221º, 2532 m, 7 August 2019 (fl, fr), A. Castro-Castro, J.G. Zavala-Pérez & J. Hernández-Rendón 4494 ( CIIDIR!, IBUG!, MEXU!). Súchil: 5.8 km al SO de San Juan Michis camino al Temascal, 23º24’N, 104º11.023’W, 2377 m, 16 September 2005 (fl, fr), A. Rodríguez & A. Castro-Castro 4525 ( IBUG!).

Figures

FIGURE 1. Polianthes montana Rose. A. Habit. B–D. Perigone views. E. Capsules. Pictures: Arturo Castro-Castro.

FIGURE 2. Geographic distribution of Polianthes subgenus Polianthes. A. Detail of P. aarodriguezii type locality. Biogeographic regionalization according to Morrone et al. (2017). Prepared by Yeri Julieta Vargas Soto and Margarita Valenzuela Hernández.